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Related papers: Unitary designs in nearly optimal depth

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We define and construct efficient depth-universal and almost-size-universal quantum circuits. Such circuits can be viewed as general-purpose simulators for central classes of quantum circuits and can be used to capture the computational…

Computational Complexity · Computer Science 2008-04-16 Debajyoti Bera , Stephen Fenner , Frederic Green , Steve Homer

The accurate evaluation of diagonal unitary operators is often the most resource-intensive element of quantum algorithms such as real-space quantum simulation and Grover search. Efficient circuits have been demonstrated in some cases but…

Quantum Physics · Physics 2015-06-16 Jonathan Welch , Daniel Greenbaum , Sarah Mostame , Alán Aspuru-Guzik

In order to assess potential advantages of quantum algorithms that require quantum oracles as subroutines, the careful evaluation of the overall complexity of the oracles themselves is crucial. This study examines the quantum routines…

Quantum Physics · Physics 2025-04-29 Sven Danz , Tobias Stollenwerk , Alessandro Ciani

Current noisy intermediate-scale quantum (NISQ) devices can only execute small circuits with shallow depth, as they are still constrained by the presence of noise: quantum gates have error rates and quantum states are fragile due to…

Quantum Physics · Physics 2024-06-11 Shihao Zhang , Kai Huang , Lvzhou Li

Quantum computational pseudorandomness has emerged as a fundamental notion that spans connections to complexity theory, cryptography and fundamental physics. However, all known constructions of efficient quantum-secure pseudorandom objects…

Quantum Physics · Physics 2025-07-28 Soumik Ghosh , Sathyawageeswar Subramanian , Wei Zhan

We investigate protocols for generating a state $t$-design by using a fixed separable initial state and a diagonal-unitary $t$-design in the computational basis, which is a $t$-design of an ensemble of diagonal unitary matrices with random…

Quantum Physics · Physics 2014-05-27 Yoshifumi Nakata , Masato Koashi , Mio Murao

Quantum oracles are widely adopted in problems, like query oracle in Grover's algorithm, cipher in quantum cryptanalytic and data encoder in quantum machine learning. Notably, the bit-flip oracle, capable of flipping the state based on a…

Quantum Physics · Physics 2025-12-02 Buji Xu , Junhong Nie , Xiaoming Sun

We study the formation of short-depth designs beyond the unitary group. We provide a range of results on several groups of broad interest in quantum information science: the Clifford group, the orthogonal group, the unitary symplectic…

As a cornerstone for many quantum linear algebraic and quantum machine learning algorithms, controlled quantum state preparation (CQSP) aims to provide the transformation of $|i\rangle |0^n\rangle \to |i\rangle |\psi_i\rangle $ for all…

Quantum Physics · Physics 2023-05-17 Pei Yuan , Shengyu Zhang

GCD computations and variants of the Euclidean algorithm enjoy broad uses in both classical and quantum algorithms. In this paper, we propose quantum circuits for GCD computation with $O(n \log n)$ depth with O(n) ancillae. Prior circuit…

Emerging Technologies · Computer Science 2013-04-30 Mehdi Saeedi , Igor L. Markov

Unitary decomposition is a widely used method to map quantum algorithms to an arbitrary set of quantum gates. Efficient implementation of this decomposition allows for translation of bigger unitary gates into elementary quantum operations,…

Quantum Physics · Physics 2024-03-14 A. M. Krol , A. Sarkar , I. Ashraf , Z. Al-Ars , K. Bertels

Constructing ensembles of circuits which efficiently approximate the Haar measure over various groups is a long-standing and fundamental problem in quantum information theory. Recently it was shown that one can obtain approximate designs…

Quantum Physics · Physics 2025-06-23 Maxwell West , Diego García-Martín , N. L. Diaz , M. Cerezo , Martin Larocca

Simulation of materials is one of the most promising applications of quantum computers. On near-term hardware the crucial constraint on these simulations is circuit depth. Many quantum simulation algorithms rely on a layer of unitary…

Decoupling has become a central concept in quantum information theory with applications including proving coding theorems, randomness extraction and the study of conditions for reaching thermal equilibrium. However, our understanding of the…

Quantum Physics · Physics 2018-02-06 Winton Brown , Omar Fawzi

In this work, we study distributions of unitaries generated by random quantum circuits containing only symmetry-respecting gates. We develop a unified approach applicable to all symmetry groups and obtain an equation that determines the…

Quantum Physics · Physics 2024-10-16 Hanqing Liu , Austin Hulse , Iman Marvian

We study the problem of efficiently learning an unknown $n$-qubit unitary channel in diamond distance given query access. We present a general framework showing that if Pauli operators remain low-complexity under conjugation by a unitary,…

Quantum Physics · Physics 2026-04-07 Sabee Grewal , Daniel Liang

This paper addresses the problem of designing universal quantum circuits to transform $k$ uses of a $d$-dimensional unitary input-operation into a unitary output-operation in a probabilistic heralded manner. Three classes of protocols are…

Quantum Physics · Physics 2020-04-16 Marco Túlio Quintino , Qingxiuxiong Dong , Atsushi Shimbo , Akihito Soeda , Mio Murao

Quantum $k$-minimum finding is a fundamental subroutine with numerous applications in combinatorial problems and machine learning. Previous approaches typically assume oracle access to exact function values, making it challenging to…

Quantum Physics · Physics 2025-10-03 Minbo Gao , Zhengfeng Ji , Qisheng Wang

Quantum state preparation is an important subroutine for quantum computing. We show that any $n$-qubit quantum state can be prepared with a $\Theta(n)$-depth circuit using only single- and two-qubit gates, although with a cost of an…

Quantum Physics · Physics 2023-04-25 Xiao-Ming Zhang , Tongyang Li , Xiao Yuan

Randomized benchmarking is a useful scheme for evaluation the average fidelity of a noisy quantum circuit. However, it is insensitive to the unitary error. Here, we propose a method of randomized benchmarking in which a unitary t-design is…

Quantum Physics · Physics 2017-12-13 Linxi Zhang , Chuanghua Zhu , Changxing Pei